Electrical testing instrument



kMay 2, 1939. w. R. sTEELE I ELECTRICAL TESTING INSTRUMENT A Filed Jun 2e, 1957" NMA Illllllilllllllilll ,lill

hw N new. 1 nu NMN Patented Mey 2,1939

UNITED''STATES- VPA'rEii'if osi-ics 2,156,319 y ELECTRICAL 'nismo ms'rnmmN'r Walter R. Steele, Lemon Grove. Calif. Application .nine 23,1937, serial Nt. 150,642

y 4 claims. This invention relates to electrical devices and pertains particularly to a. testing or "troubleshootingv device.

'Ihe primary object of the present invention is 5 to provide an electrical tester or trouble indicat- `l5 may be readily carried in the pocket.

A still further object of the invention is to provide in a trouble indicating' instrument of the character referred to a novel detachable connection by means of which a lead wire may be read- 20 ily coupled electrically with either oi' two terminals for use in making two distinct tests with the instrument, such as testing kfor continuity in an electrical circuit, and testing by means oi' a neon tube built into the device, for voltage and 85 plcarity in either a direct or alternating current c uit.

A still further object of the invention is to provide a novel form of tester tip wherein the tip .whensecured in place in a holding body, may at i 80 the same time firmly secure in an` electrical con- .nection with itself one end of an electric current carrying wire forming a part of the device.

Still another object of the invention is to provide in an instrument having a ilxed tester tip $5 and a movable tip. a novel supplementary tip adapted for electrical connection with one ofthe first mentioned tips, whereby the tips may be secured toa wire, terminal post, or other electric current carrying unit so that the user of the de- 40 lvice may have his hands free for other-work.

. The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawing forming part of this specification, withy the invention.

(Cl. F15- 183) Fig. 2 is a view partly in longitudinal section and partly in elevation oi the casing portion of the instrument.

Fig. 3 is a view in longitudinal section through a test tip. s

Fig. i is a view in longitudinal section through a' test tip connector.

Fig. 5 is a' longitudinal sectional view oi a modified form or a portion of the instrument.

Fig. 6 shows a modification of the test tip con- 10 nector.

hllilg. 7 is a detail of a portion of the casing Fig. 8 is a view in elevation oi' a connector clip. Fig. 9 is a view showing the sliding contact in lo operative position.

Referring now more particularly to the drawing, the numeral'l designates the housing or casing of the present device which is formed of some suitable insulation material such as nbre, elite 20 or the like and which is relatively long and o! circular Across-sectional design in simulation vof the usual .flashlight casing. Secured within and extending throughout a major portion f of the length of the casing is a tubular or metalliclin- 25 ing 2 which at one end is threadably engaged with the wall of the casing and is interiorly formed to provide screw threads I. This threaded portion I of the lining has threadablyengaged therewith the menu sleeve 4 which intermediate its ends is $0 provided with the surrounding nange I which normally bears against the end of the casing I and maintaining a portion oi the sleeve I extended beyond the adjacent end'ot the casing. nils extended portion oi the sleeve has threa'dably 35 coupled therewith the cap i which is open at its outeryend, as indicated at 1.- The outer end of the sleeve 4 is formed to provide a threaded collar or socket l for the reception of the threaded base portion of an electric incandescent iight I. and when this light is threaded in position in the socket and the cap'l is threaded onto the `extended end of the sleeve I, the bulb portion o! the electric light or lamp will be in position to project light rays through the opening'l when the lamp 45 is energized.

Adjacent the end of the casing I nearest the lamp I, the casing wall is provided with the keyhole slot Il and immediately above this slot the uninnnusdmiieriyiormeddet inereidend sothe portions of the metal lining bordering the narrow partof this latter slot Il arepressed or sprung inwardly on each side. as indicated at I2, for a www toA be hereinafter dcribed.

Adiseentthetransversecenterotthe casingi Il a m opening n which n elongated longitudinally strip Il which is interposed between the liningV 2 and the inner side of the casing I. I'his strip Il has one `end extended beyond the end of the lining and turned to form the inwardly projecting contact finger Il. Adjacent the finger the strip Ii has the inwardly pressed tip I1 which, when the strip I5 is shifted in one direction is adapted to ride into a vreceiving depression I9 formed in the lining 2 so as to frictionally hold the contact and strip in the shifted position.

One or more electric batteries or dry cells I9 are placed in the casing and within the cylindrical lining 2 with the terminal of one battery in electrical contact with the center terminal of the electric lamp 9.and the opposite terminal of the battery positioned so that when the contact strip Il is shifted toward the lamp 9 the nger II' will be brought into electrical contact therewith and thus complete an electric circuit` through the sleeve 4 to oneside of the lamp and out of the opposite side of the lamp to and through the battery or batteries back to the terminal nger I9. It is preferred that the sliding contact strip Il be formed prior to its installation with a longitudinal bow so that when it has been placed between theA lining 2 and the wall of the casing I, it will exert a suillcient pressure against these two bodies to hold it against accidental movement. This action will be supplemented by the use of the .struck-cut portion II and the recess IB for holding the strip in circuit-closing position when the button I4 is shifted in the proper direction.

If desired the strip -II may also be provided with an outwardly struck portion or lug 2 0 which may engage in the notch or recess 2| in the adjacent surface of the casing wall when the contact strip has been shifted in a direction tobreak :he electric circuit formed for energizing the lamp Insertedinto the opposite end of the casingv I is an elongated body of insulation material which is indicated by the numeral 22. This body has an outer tapering end portion in which a longitudinal bore is formed, as indicated at 29, and this bore communicates by means of the central passage 24. with a chamber 25 formed in the b'ody and opening through the inner end thereof.

Secured in any suitable manner in the bore 2l is a-metallic sleeve 2G, which isinteriorly threaded adjacent its outer end and adjacent its inner end is provided with a constricted portion 21 which forms a lsubstantially conical shoulder as shown. While. any suitable meansmay be employed for securing the sleeve 2l in place. it is preferred that it be provided with .a series of prongs 2l arranged to point toward one end of the sleeve and thus when the sleeve is forcibly inserted into the bore 29 with'the prongs directed toward the outer end ofthe b0re. .it will be seen that they will operate to prevent the removal of the sleeve.

The numeral 29 indicates a fixed tester tip which ispointed at one end and which at its other end or adjacent thereto has the enlarged threaded portion 30 which is adapted to engage in the threaded portion of the sleeve 2B. 'I'he end of the tester tip adjacent the threaded portion I0 is tapered so as to seat on the conical shoulder formed at 21 and by this arrangement an end of i a current conducting wire may be rmly secured in electrical connection with the tip 29 by placing the end between the shoulder 21 and'tlle tapered inner end of the top and then threading this tapered end in until it compresses the end of the wire against the shoulder. Such a wire, as indicated by the 'numeral 3l, is carried through the passage 24 through the lateral passage 32 into the channel 92 which extends along one side of the insulation body 22. If the wire 3l is of the multiple strand type, then a particularly effective 'electrical connection may be established between the inner end of the tip 29 and the sleeve 2t by fraying out the end oi the wire and spreading the strands on .the shoulder 21 so that the tapered inner end of the tip .'will enter the center of the group of strands'and compress them at diiferent points against the shoulder.

Adjacent the inner end of the groove Il an electric terminal in the form of a rivet 34 is secured which passes from the groove through the material of the body 22and into the chamber 25.

end of the electric cell or battery I9. The arm performs the double function of `constantly forcing the cell or cells into rm electrical contact with the end of the lamp 9 and also provides an electrical connection between one side of the battery wall and the wire 9| which leads to the tester tip 29. The numeral 36 designates an insulation covered electric wire of the high-tension type, one end of whichis electrically secured to the head of a button 91. This button has an inner or base portion 98 which is connected with the head by a narrow intermediate web and the base of the .button is adapted to be inserted into the larger part'of the key-hole slots I0 and II and then shifted into the narrower portion of these slots so that the base will be made to firmly electrically connect with the sprung-up portion I2- of the lining 2 and thus electrically couple the wire 99 .'tnerewmi. ai the opposite end or this wire as a metallic collar is located and has the end of the wire frictionally engaged therein. This collar is indicated by the numeral 39 and has secured therein the metallic sleeve 29' which is a dupli cate 'of the sleeve 26 previously referred to and,

which also carries a tester tip 29' and secured in the same manner in the sleeve.

The elements of the instrument thus far de# scribed provide ilrst a flashlight of usual construction, Aand second a means of testing con-v tinuity in an electric circuit. The operation of the device as a flashlight will be obvious, and in using the device as a continuity tester, it will be are placed, from one tip through the spring arm I5, the battery or dry cell and the electric lamp. backthrough the lining 2 and through the wire I8 to the other tip 29' and thru the suspected portion of the electric circuit to the original or first mentioned tip 29.

Housed in the chamber 25 is a small neon bulb 40. Such a bulb has two electrodes, as is well known, and one of these is electrically connected by the wire 4I with the terminal rivet 34, While the other electrode is connected by the wire 42 with one side 'of a resistance 43 which is housed in a suitable recess in the side of the insulation body 22 and in an area of the same where it will be covered by the casing I. This resistance is preferably in the form of a small strip resistor Adjacent the resistance unit 43l a recess 44 is formed in the side of the body,22 andse- `the strip 45. This strip is electrically coupled y with the other side of the resistance unit 43.

When it is desired to use thedevice as an indicator of the approximate voltage in 'an electric circuit, the terminal button 31 is slipped into the slot ylli with the base por-tion 39 lying against the` inner side of the slotted contact 45. The portions of this contact on either side of the slot are preferably bowed inwardly 'slightly so that a 'firm electrical connection will be established with the button base 38. The tips 29 and 29 are then employed as points or terminals for bringing current in to the neon glow lamp 49 and carrying it back to its source, and the `approximate voltage of current passing through the lamp will be indicated by the brightness of the glow developed. This portion of the instrument will indicate if there is a voltage, unless the same isv very low, whether the same as of A. C. or D. C. type and the polarity. It will also indicate the approximate frequency of an alternating current and may also be used for locating faults in radio testing, as for instance, shorted condensers and for resonance indications in radio broadcasting equipment and wave meters. In testing a direct current line one only M the two electrodes of the glow lamp will glow when vcurrent ilows therethrough and both electrodes will glow when the current is of the alternating variety and the frequency of current will be indicated by the frequency of the icker developed in the lamp.

In order thatthe operation of'the glow lamp may be readily seen, the casing is `provided with lng which lea'ds into the chamber 25, or instead and entering the large bore.

of forming'this chamber as a' bore in the inner end oi the body 22, it may be in the form of a longitudinally extending slot which is carried through from one side of the body tothe other, in which case the window opening 41 will be located over one open side of the slot.

In making tests, it is frequently of advantage for the person using the instrument to haveboth hands free and in order to facilitate the use of the instrument and still have the hands free for other work, there-are provided two tester clips, one of which is illustrated in Fig. 4, and indicated generally by the numeral 48. This clipconsists of a short cylindrical body 49 of insulation material having a relatively large bore formed there-'- in from one end. as indicated at 50, and a small bore formed longitudinally in the other end Extending across the bore 50 is a partition web Il' and thel bore 59 has inserted thereinto upon each side of the web 5l', the electric current conductor strip 52 which is reversely bent at its inner end to form the hook portion'53, the tip 54 of which engages in a suitable notch in the wall of the bore soas to l tion as the body 22.

prevent the strip from being accidentally withdrawn. Adjacent each end of the hook portion 53 of each strip, the wall of the body 49 is provided with an opening 55 thru which a pin may be inserted to remove the tip 54 from the wall notch and thus permit the withdrawal of the strip. The other ends of the strips 52 extend a substantial distance beyond the adjacent end of the body 49 and each is formed as a hook 56.

These hooks 56 are in opposed relation and a's shown one is slightly larger than the other sothat engagement of a wire or terminal post between the same may be easily eifected by hooking the end of the larger hook 55 against the post and exerting a pull to eifect the separation of the hooks whereupon the post may be caused to easily slip between the two opposed portions.

The lauxiliary bore 5| is adapted to receive a tester tip 29 or 29 and the space between the strips 52 is slightly less than the diameter of the tester tip so that the latterr will be forced into firm electrical engagement with the two strips and the tester tip clip will be firmly secured to the tester tip.

In the illustration of the tester tips the same are shown as .being formed adjacent the outer end of the threaded portion 30, of polygonal cross-section whereby the tip may be easily grasped by pliers or a wrench so as to screw the inner end of the tip firmly into position against the shoulder 21. It is to be understood, however, that this particular portion of the tester tip may be in the form of a knurled head whereby the tip may be readily secured into position by hand and without requiring the use oi either `of the tools above referred to.

In Fig. 5, there is illustrated a slightly modified form of neon tube, the same being shown in position vin a chamber 25' formed in the inner end of a body 22 which is of the same construc- In this form the neon tube consists of a transparent cylinder 51 at each end of which is a metallic terminal 58. One of these terminals is in direct electrical connection with a slotted contact member 45 while the other terminal 58 is in direct electrical connection with the rivet 34'. In this form of neon tube the use of a. resistance unit is not necessary,

tube previously referred to and indicated by the numeral 40. While this latter type or lamp may be'preferable, it is contemplated to cover the use of both forms and the use in connection with the first mentioned form of the resistance unit.

In Fig. 6 there is illustrated a slightmodicationv of the tester clip, indicated generally by' the numeral 49. In this form the body and interior construction is the same as in the form previously described and the same will therefore be generally designated by the numeral 48 but the metallic current carrying strips extend.- ing from the end of the body and here indicated by the numerals 52' terminate in semi-circular portions 59 which have their ends in opposed relation and normally in contact and these ends are each provided with a transverse groove 9.

These grooves together form a circular or other Y open the slotted or grooved jaws to facilitate the placing of a. wire and maintain a iirm electrical connection therewith.

From the foregoing it will be readily apparent that the instrument hereindescribed. because of the novel character of the several elements ci which it is made up, may be constructed in small and compact form and also that with it a large number of tests may be made upon various types of electrical devices which would under other circumstances require a relatively large amount oi equipment. means might be Worked out for changing the electrical connection of the button 31 from the lining 2 to the terminal 45 by means -oi a switch, but such a change-over means is undesirable because of the possibility of the user forgetting how the switch is set and burning out the electric lamp 9 by the passage of a current therethrough which was intended to pass through the neon lamp and the resistance. With the method illustrated and described for changing the connections for the wire 36, such an error cannot occur because theA operator will know by the feel of the instrument how the wire 36 is connected and will at once be aware if a change should be made before making the test under consideration.

By -the provision of the novel wire securing means in the tip 39, as is illustrated in detail in lFig. 3, it will be apparent that an easy and quick connection may be made between this tip and a cable such as the one indicated by the numeral 36, where the latter is of the type having a stranded wire. By removing a portion of the insulation from around the end of the stranded wire and inserting the wire with the adjacent portion of the insulation into the end of the sleeve 26', the portion of the wire which has been bared will pass through the end of the sleeve 26 past the shoulder` and when the pointed inner end of the tip 29' is threaded inwardly to engage the shoulder, it will enter the center of the end of the stranded wire and separate the strands to clamp them against the adjacent shoulder of the sleeve.

By providing the hooks 56 of the test tip clip in the novel manner iliustrated, it will be apparent that the hooks may be secured to a post or other body without slipping and also that by spreading the hooks apart, the wire may be inserted between the jaws which are situated inwardly-of the hooks and iirmly held between the teeth of the jaws.

The tongs 56 of the tip clip illustrated in Fie. 4 are preferably formed with their ends notched or provided with a semi-circular cut-out, so that the ends of these tips may be engaged securely with a terminal post. This construction is similar to the construction illustrated and described in connection with the modied form of Fig. 6.

At the inner ends oi the tongs 56 the toothed jaws have their forward ends merging with curved shoulder portions, as illustrated, so as to facilitate slipping the tongs over a wire to enable the operator to' secure the device to a hot" wire without the necessity of opening the jaws with his ngers and thus running the risk of getting a shock.

I claim:

1. In an electric testing instrument, an elongated casing, an incandescent electric lamp mounted in one end thereof, an electric battery within the casing and connected at one side with one side of the lamp, said casing having a slotl in the wall thereof adjacent said lamp, an electric current conductor extending from said slot to and engaging the other side of the lamp, a body It is, of course, understood that aussie securedin the other end of the casing, a testing point secured in and projecting from said body, a current carrying spring arm carried by said body and electrically engaging the other side of said battery, said arm being electrically coupled with said test point, a flexible current conductor having a test point at one end, and means at the other end of tre exible conductor for frictional engagement in said slot and electrical connection with said first electric current conductor adjacent thereto.

`2. In an electric testing instrument, an elongated casing, an incandescent electric lamp mounted in one end thereof, an electric battery within the casing and connected at one side with one side of the lamp, said casing having a slot in the wall thereof adjacent said lamp, an electric current conductor extending from said slot to and engaging the other side of the lamp. a body socured in the other end of the casing, a testing point secured in and projecting from said body, a current carrying spring arm carried by said body and electrically engaging the other side of said battery, said arm being electrically coupled with said testing point, a flexible current conductor having a testing point at one end, means at the other end of the exible conductor for' frictional engagement-in said slot and electricai connection with said first electric current conductoi" adjacent thereto, a neon glow lamp carried by said body and having two electrodes. electrical connecting means between one electrode and said rst testing tip, a resilient terminal carried by the body, electrical connecting means between said resiiient terminal and the other electrode of the glow lamp, and means facilitating the frictional engagement of the said other end of the resilient conductor with said resilient terminal consisting of a slot formed in the casing to permit the introduction of the said other end of the resilient conductor beneath the resilient terminal.

3. A testing instrument comprising a tubular body of insulation material, a metallic incandescent bulb socket in one end thereof, an electric current conducting metallic insert in the body electrically connected with said socket, a battery in the body, an incandescent buib in sai-:i socket and electrically connected on one side with one side of the battery, the other side of the bulb being electrically connected to the socket. said casing having an opening therein and said insert having a keyhole slot adjacent to and corresponding with said opening, a switch strip having sliding electrical connection with said insert and adapted when in circuit-closing position to make electrical contact with the other side of the battery, a body of insulation material irerted into the other end of the tubular body, a contact finger carried by said inserted body and pressing against the said battery and having electricalconnection with the said. other side thereof and maintaining the battery in operative position, a rigid test point carried by said inserted body and electrically connected with said nger, a gas-filled glow lamp housed entirely in said inserted body and viewable thru a window opening formed in the sides or" the tubular and inserted bodies, an electrical connection between one side oi' said glow lamp and said nger, a resilient terminal clip carried by the inserted body and electrically coupled with the other side of the glow lamp, and an elongated conductor 'having a test point at one end and a terminal button at the other end which terminating at one end at an end of the casing and formed to provide interior screw threads, a

lamp socket metallic shell having exterior screw threads and having oneend in and engaging the threads of said liner, a threaded sleeve` disposed centrally of the shell and electrically connected therewith, said sleeve being adapted to receive the base of an incandescent bulb, a hood threaded onto the outer end of said shell and having an opening thru which light rays may pass from a bilb in said sleeve, switch means electrically coupled with said liner for establishing an electrical A connection with one side of a battery in the liner, the other side of the battery being adapted to contact a terminal of a bulb in the sleeve, a keyhole slot formed in the casing and said liner, an insulation body inserted in the other end of the easing, a spring linger carried by said inserted body and adapted to electrically contact the said vother side of gaia battery and to maintain the battery in position, a rigid test point carried by said inserted body and electrically connected with said linger, and a flexible current conductor carrying a test point on one end and carrying a terminal button on its other end, said button being adapted to enter said keyhole slot for electrical connection with said liner.

WALTER R. STEELE. 

